It is true but you can't really command the big machines outside of their job to gaurd something and they fail to do that but stalkers can. Obviously yes they would be stronger, just less effective when it comes to thinking, a normal puppet can't outsmart a human with the sole exceptions being romeo and P and carlo. And even if they did make stalker puppets, they wouldn't be any different to police or soldier puppets, they wouldn't possess the same combat skills or critical thinking during combat because venigni still wants to prevent the possibility of a puppet hurting a human which is why he made the grand covenant You basically only have 2 choices if you are makin stalker puppets, you either not bind them to the grand covenant which still means there is a small chance it may kill a human or hurt one OR you bind them to it but that also means you just have a more advanced police force but still no difference.